This invention relates to beading and, in particular but not exclusively, to the beading of cans using roll/rail and roll/roll beading systems.
Container body beads are formed by a beading machine of, for example, the rotary turret type, in which a container is mounted on a mandrel and rolled over fixed rail segments progressively to form beads in the container side wall. The beading rail is profiled to form the beads as the can body is forced against the rail. The internal mandrel, or alternative male tool element, has a complementary profile to that of the rail. Alternatively, beads may be formed by the relative motion of external rollers (also referred to simply as “rolls”) and an internal mandrel, the container being mounted and freely rotatable on the mandrel.
Can performance is typically quantified in terms of axial collapse and panel performance (distortion from the original, e.g. circular, cross-section under unbalanced external pressure). Whilst conventional beaded cans provide acceptable axial and panel performance, there is a need to improve performance still further in order to enable additional metal savings to be made.